Backport: Add sleep functionality (#64)

[pablogs9]

Backport of #64

[pablogs9]

Hello, @JanStaschulat could you check this backport? This is blocking micro-ROS CI.

[codecov-commenter]

Codecov Report

Merging #89 (7d6a39b) into foxy (1007674) will increase coverage by 0.05%.
The diff coverage is n/a.

@@            Coverage Diff             @@
##             foxy      #89      +/-   ##
==========================================
+ Coverage   29.44%   29.49%   +0.05%     
==========================================
  Files          53       55       +2     
  Lines        5430     5434       +4     
  Branches     2736     2736              
==========================================
+ Hits         1599     1603       +4     
  Misses       1533     1533              
  Partials     2298     2298              

Impacted Files	Coverage Δ
ros_ws/src/lddjil3u79/rclc/rclc/src/rclc/timer.c
...rclc_lifecycle/src/rclc_lifecycle/rclc_lifecycle.c
...l3u79/rclc/rclc/test/rclc/test_executor_handle.cpp
...c/rclc_examples/src/example_executor_convenience.c
...p9qgs4/rclc/rclc_lifecycle/test/test_lifecycle.cpp
.../src/gxe8kp9qgs4/rclc/rclc/src/rclc/subscription.c
...src/lddjil3u79/rclc/rclc/test/rclc/test_client.cpp
.../src/gxe8kp9qgs4/rclc/rclc/test/rclc/test_init.cpp
ros_ws/src/gxe8kp9qgs4/rclc/rclc/src/rclc/client.c
.../rclc/rclc_examples/src/example_executor_trigger.c
... and 98 more

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[pablogs9]

Kindly ping @JanStaschulat @ralph-lange